NWHG Ref. 050 — Loch Sionascaig

Location, grid reference and photograph

Loch Sionascaig is a large remote loch lying within Inverpolly, roughly halfway between the A 835 and the west coast, Grid Ref. [NC 120 140].

(Figure 44) Classic Lewisian gneiss cnoc-and-lochan landscape around Loch Sionascaig viewed from the summit of Cul Beag. The Torridonian sandstone inselbergs of Cul Mor and Suilven are seen on the right. BGS Photo P530413 — T Bradwell

GCR site reference, block, volume and notified feature of SSSI?

GCR Ref. 2747, Quaternary Block, Vol, 6. Notified feature of Inverpolly SSSI.

Description and geological significance

The sediments on the bed of Loch Sionascaig and in a bog on the central island of Eilean Mor provide detailed pollen records, supported by radiocarbon dating, of vegetational changes in Scotland during the Lateglacial and Holocene (particularly important for the environmental changes it demonstrates). Loch Sionascaig is therefore an important reference site for reconstructing the environmental history of north-west Scotland during the last 13,000 years.

Accessibility

The site is many kilometres distant from the nearest road and is effectively inaccessible to the general public, requiring a very lengthy walk over difficult and arduous terrain.

Conservation

The important features occur on the loch bed and on the central island. There are no conservation requirements.

Visibility and “clarity”

The key features are only visible to specialists with suitable facilities and sampling equipment.

Interpretation and interpretation potential

There are no current interpretation facilities and the remote location and nature of the key features do not lend themselves to interpretation panels. Nonetheless, the site could be incorporated within a Geopark long-distance walking guide. There is a potential as an educational resource for students of Quaternary geology and physical geography.

Key references

BIRKS, H.J.B. 1993. Loch Sionascaig In Gordon, J. E. & Sutherland, D. G. (eds) Quaternary of Scotland. Geological Conservation Review Series, 6, Chapman and Hall, London, 137–143.